One of the most frustrating things for writers is a blank page and the lack of any "brilliant" ideas to fill it. It's not that there aren't any glimmers of inspiration, but sometimes, the cup of "fresh, innovative and exciting ideas" does not runneth over. There are so many YA books available it can feel like all the cool ideas have already been taken.
There's good news and its name is Research! There are weird and little known facts out there just begging to be made into novels. Check out the Odd News reports on Yahoo. Look at headlines and make up your own story to go with them. You can even just Google things that interest you personally and all kinds of stuff comes up. Let one link take you to another and another until you find something that sucks you in. Just keep digging around until you find gold!